1. Field of the Invention
The present invention relates to a semiconductor memory device.
2. Related Art
A ferroelectric memory is a destructive read out memory device in which data is destroyed in a data read operation. Accordingly, after the data read operation, it is necessary to perform a restore operation for writing back data. If a sense amplifier detects data, a one-directional electric field is applied between electrodes of a ferroelectric capacitor. Therefore, in the data read operation, not both data “0” and data “1” are destroyed but one of the data is destroyed.
However, in case of a conventional ferroelectric memory device, a restore period is equally provided for each of the data “0” and the data “1” in the data read operation. In the data read operation, it suffices to restore the one destroyed data. However, in a data write operation, it is necessary to equivalently write both the data “0” and the data “1”. Due to this, according to the conventional technique, the restore period is equally provided for each of the data “0” and the data “1” even in the data read operation to conform to the data write operation.